Sand is found in oil, gas, and water being produced from active wells. The sand can originate in the formation itself or be introduced into the formation during the hydraulic fracturing of the well (e.g., as proppant sand). The sand causes damage to the well site equipment and pipe line, and, therefore, many jurisdictions require sand control. Oil and gas wells are increasingly utilizing sand separators such as screens/filters.
One way to ensure that sand of a certain size is being captured is to employ a sand screen (also known as a sand filter). The sand screen is a device that has slots or holes of a certain size so that no particles larger than that slot width can pass through the device. The device is not well-suited for bulk sand removal because the screen tends to plug-up when the fluid includes large amounts of sand. As such, these devices are often employed in series or after another type of bulk removal device such as a sedimentation unit. The primary devices work well at removing most of the sand but lose effectiveness as they fill/plug-up with sand.
As particles plug the slots of the sand screen, and the flow becomes restricted, the differential pressure caused by the filter increases. As a result, production can ultimately decrease. In many cases, paraffin waxes, that are not removed by the initial stage separator, add to the problem. To reverse these effects, the flow is shut-off to the unit, and the filters are removed and manually cleaned by workers. The disassembly, filter removal, washing, and reassembly is a time-consuming and labor-intensive task and has significant danger due to trapped sour gas. Therefore, there is a need for an automated solution of cleaning the sand filters.